Renewable fuel mixture

ABSTRACT

A fuel composition comprising ethylene and alkyl esters, which may be used as a substitute for heating oil. In one embodiment, the mixture comprises 95% anhydrous ethanol and 5% B100 biodiesel. The mixture may further contain a lubricity agent.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of Provisional Patent Application No. 60/434,016 filed Dec. 16, 2002, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] This invention relates generally to a renewable fuel mixture and more specifically to a composition of ethanol and alkyl esters, suitable for use as a fuel oil substitute.

[0003] Petroleum products are currently used in a number of applications. One such application is the use of fuel oil for heating spaces, such as homes and other buildings. Approximately 7.7 million homes in the United States consumed 6.7 billion gallons of #2 heating oil in the year 2000.

[0004] The primary drawback to using heating oil is that the resource is not renewable. Continued heavy use of petroleum will eventually lead to expiration of the Earth's petroleum resources. Further, the demand for heating oil outweighs domestic production capacity, and the remainder must be imported from other countries.

[0005] Burning fuel oil releases significant amounts of greenhouse gases into the environment, and sulfur emissions contribute to the production of acid rain. Poor fuel quality and sulfur emissions can foul heating oil burners and boilers, which lowers heating system efficiency and requires frequent maintenance. Fuel oil is also toxic, and storage tanks are required to have double-lining and leak detection devices. A fuel oil spill will saturate the ground and contaminate nearby water supplies.

[0006] A non-toxic, cleaner burning fuel derived from renewable resources to be substituted for heating oil is desirable.

[0007] All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.

[0008] Without limiting the scope of the invention a general description of some of the claimed embodiments of the invention is set forth below. Additional details of the disclosed embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.

[0009] A brief abstract of the technical disclosure in the specification is provided as well, only for the purposes of complying with 37 C.F.R. 1.72. The abstract is not intended to be used for interpreting the scope of the claims.

GENERAL DESCRIPTION OF THE INVENTION

[0010] The present composition comprises a mixture of ethanol and alkyl esters that is suitable for use in existing heating systems. In the preferred embodiment, the composition comprises 95% anhydrous ethanol and 5% biodiesel (B100) by volume. The composition may further include a lubricity agent.

[0011] The composition has been found to be a suitable substitute for fuel oils, such as #1 and #2 heating oils, and may be used in existing heating oil units without modification. All components are manufactured from renewable resources that are domestically available in virtually unlimited supply. The composition is non-toxic, virtually free of sulfur, and burns cleaner than heating oil.

[0012] These and other embodiments which characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages and objectives obtained by its use, reference should be made to the drawing which forms a further part hereof and the accompanying descriptive matter, in which various embodiments of the invention are described.

BRIEF DESCRIPTION OF THE DRAWING

[0013] A detailed description of the invention is hereafter described with specific reference being made to the drawing.

[0014]FIG. 1 is a flowchart depicting a process that may be used to obtain the composition.

DETAILED DESCRIPTION OF THE INVENTION

[0015] While this composition may be embodied in many different forms, there are described in detail herein specific preferred embodiments. This description is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments described.

[0016] The present inventive fuel composition 60 comprises a mixture of ethanol 30 and alkyl esters 50. A preferred embodiment of the fuel composition 60 comprises 95% anhydrous ethanol and 5% B100 biodiesel by volume. The composition according to this ratio may have the following characteristics: Auto Ignition Temperature 683° F. Boiling Temperature  78° C. Flashpoint  48° F. Specific Gravity .785 BTUs per Gallon 65000

[0017] The fuel composition 60 has been found to be a desirable alternative to fossil fuel oils used to heat interior spaces. The fuel composition 60 is desirably used as an alternative to #1 fuel oil or #2 fuel oil. It may be used in conventional heating systems designed for use with heating oil without modification of any parts. In some applications, it may be desirable to adjust characteristics of spray nozzles utilized, such as orifice diameter and spray angle, to optimize the spray pattern for efficiency in burning an inventive fuel composition 60. Fuel pressure may also be adjusted in optimizing the burning system.

[0018] All components of the fuel composition 60 may be manufactured from renewable resources that are domestically available in virtually unlimited supply. Although the individual components may be manufactured using a variety of methods, preferred methods are described below.

[0019] Ethanol 30 may be manufactured from a number of renewable agricultural materials 10, such as corn, barley or wheat. During the milling phase 12, the agricultural material 10 may be ground into a fine powder or meal. The meal is liquefied during a liquefaction process 14, wherein the powder may be mixed with water and an enzyme such as alpha-amylase. The mixture is heated, desirably to an initial high temperature of 120°-150° C. for reduction of bacteria levels. The mixture may then be held around 95° C. for a period of time sufficient to allow complete liquefaction of the starch.

[0020] The liquefied starch in the resulting mash is converted to fermentable sugars during a saccharification process 16 by a secondary enzyme, such as gluco-amylase. Yeast is then added for fermentation 18, wherein the sugars are converted into alcohol. The resulting fermented mash or beer contains approximately 10% alcohol, as well as the non-fermentable solids from the agricultural material 10 and the yeast cells.

[0021] Next, the beer is distilled 20 to remove the alcohol, which at this stage generally contains approximately 96% ethanol. The alcohol may be subject to a dehydration process 22 to remove excess water. The resulting ethanol 30 is desirably pure anhydrous ethanol of approximately 199 to 200 proof.

[0022] According to government regulations, the ethanol 30 may be required to be denatured, thereby making the product unfit for human consumption. Typically a small amount of denaturing product, such as gasoline, will be added to the ethanol 30. The denaturing product generally accounts for approximately 2-5% of the volume of the denatured ethanol. It should be understood that pure ethanol and denatured ethanol are both suitable to be used in the fuel composition 60.

[0023] The alkyl esters 50 used in the fuel composition 60 desirably comprise B100 biodiesel conforming to ASTM Specification D 6751. Alkyl esters 50 may be manufactured through the transesterifications of organically-derived raw lipids 40, such as vegetable oils, used cooking oils and animal fats.

[0024] A mixture of alcohol and a catalyst are reacted with the raw lipids 40 during a reaction process 42. Typically sodium hydroxide or potassium hydroxide is dissolved in methanol, and the mixture is charged into a closed reaction vessel with the raw lipids 40. The reaction generally takes place over a time period of 1 to 8 hours. The total time required depends upon a number of variables. Generally, keeping the reaction mix at a temperature above the boiling point of alcohol, 160° F., will speed the reaction.

[0025] When the reaction phase 42 is complete, a mixture of glycerin and crude biodiesel will have formed. The two products are then separated 44. The crude biodiesel at this stage generally contains excess methanol used in the reaction. During purification 46, the excess methanol is removed by distillation or by a flash evaporation process. The remaining alkyl esters 50 desirably comprise B100 biodiesel that conforms to ASTM Specification D 6751.

[0026] The final fuel composition 60 comprises a blend of ethanol 30 and alkyl esters 50. Although any proportion of ethanol 30 and alkyl esters 50 that is suitable for the intended purpose may be used, the preferred proportions range from 90% ethanol and 10% alkyl esters to 98% ethanol and 2% alkyl esters. The composition may further include a lubricity agent 58 in an amount sufficient to provide lubrication. A lubricity agent 58 may comprise any additive capable of providing lubrication, and desirably comprises a soy-based lubricant such as Synergol™ FLA available from International Lubricants Inc. of Seattle, Wa. When using Synergol™ FLA as a lubricity agent 58, a quantity of 50 to 1000 ppm may provide appropriate lubrication. Preferably, a quantity of 250 to 500 ppm may be used.

[0027] In one embodiment, the fuel composition 60 comprises a blend of ethanol and alkyl esters at a ratio of 19:1, which may be formed by mixing 95% anhydrous ethanol with 5% B100 biodiesel by volume. The mixture at this ratio will blend readily and without agitation. A lubricity agent 58 may further be added, such as Synergol™ FLA at 250 to 500 ppm.

[0028] Testing has shown that the present fuel composition 60 remains viable as a fuel oil substitute after being stored for over a year. It is projected that the fuel composition 60 is capable of remaining in storage indefinitely. The fuel composition 60 is capable of being stored and burned in ambient temperatures of less than 15° F.

[0029] The above disclosure is intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in this art. All these alternatives and variations are intended to be included within the scope of the claims where the term “comprising” means “including, but not limited to”. Those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the claims.

[0030] Further, the particular features presented in the dependent claims can be combined with each other in other manners within the scope of the invention such that the invention should be recognized as also specifically directed to other embodiments having any other possible combination of the features of the dependent claims. For instance, for purposes of claim publication, any dependent claim which follows should be taken as alternatively written in a multiple dependent form from all prior claims which possess all antecedents referenced in such dependent claim if such multiple dependent format is an accepted format within the jurisdiction (e.g. each claim depending directly from claim 1 should be alternatively taken as depending from all previous claims). In jurisdictions where multiple dependent claim formats are restricted, the following dependent claims should each be also taken as alternatively written in each singly dependent claim format which creates a dependency from a prior antecedent-possessing claim other than the specific claim listed in such dependent claim below.

[0031] This completes the description of the preferred and alternate embodiments of the invention. Those skilled in the art may recognize other equivalents to the specific embodiment described herein which equivalents are intended to be encompassed by the claims attached hereto. 

1. A heating oil substitute comprising: ethanol; and alkyl esters.
 2. The composition of claim 1, wherein the ethanol is denatured.
 3. The composition of claim 1, wherein the ethanol is anhydrous.
 4. The composition of claim 1, comprising: a range from 90% ethanol and 10% alkyl esters by volume to 98% ethanol and 2% alkyl esters by volume.
 5. The composition of claim 1, the ethanol comprising about 95% of the composition by volume and the alkyl esters comprising about 5% of the composition by volume.
 6. The composition of claim 1, the alkyl esters comprising biodiesel fuel.
 7. The composition of claim 6, wherein the biodiesel fuel conforms to ASTM Specification D
 6751. 8. The composition of claim 1, further comprising a lubricity agent.
 9. The composition of claim 8, the lubricity agent is provided in a range from 50 ppm to 1000 ppm.
 10. The composition of claim 9, the lubricity agent comprising 500 ppm.
 11. The composition of claim 8, wherein the lubricity agent is derived from soy.
 12. A fuel composition comprising a range from 90% ethanol and 10% alkyl esters by volume to 98% ethanol and 2% alkyl esters by volume.
 13. The composition of claim 12, wherein the ethanol is anhydrous.
 14. The composition of claim 12, the alkyl esters comprising biodiesel fuel.
 15. The composition of claim 14, wherein the biodiesel fuel conforms to ASTM Specification D
 6751. 16. The composition of claim 12, further comprising a lubricity agent.
 17. The composition of claim 16, the lubricity agent is provided in a range of 250 to 500 ppm.
 18. The composition of claim 16, the lubricity agent comprising 500 ppm.
 19. A method of heating an area comprising burning a mixture of ethanol and alkyl esters. 